The invention relates to a method for treating waste material, in which method waste material is supplied to an apparatus where a conical rotor is placed between stators, and whereby at least the stators have recesses by means of which the material can be transferred through the apparatus when the rotor is rotated, and which rotor has several openings in the axial direction, in which case at least some of the material is conducted through the openings.
The invention further relates to an apparatus for treating waste material, which apparatus comprises a conical rotatable rotor placed between stators, whereby at least the stators have recesses by means of which waste material moves through the apparatus when the rotor is rotated, and which rotor has several openings in the axial direction through which openings at least some of the material is arranged to pass.
WO 97/21532 discloses an apparatus where a conical rotor is placed between two stators. Helical grooves are arranged in the rotor and/or the stator for extruding the material to be extruded from the extruder when the rotor rotates. Furthermore, an opening or openings are arranged in the travel of the rotor, through which openings at least some of the material to be extruded is arranged to flow. The material to be extruded is made homogenous by means of the apparatus, but the treatment of waste material is inefficient with this apparatus. By arranging a sharp pitch angle for the grooves of the rotor, the material will be ground to some extent at the nozzle of the supply conduit, but this kind of a solution cannot be applied efficiently to the treatment of waste material.
Finnish Patent Application 960,589 also discloses an apparatus where a conical rotor is arranged between two stators. At the nozzle of the supply conduit, the rotor has openings through which at least some of the material to be supplied can flow. By arranging the opening to be oblique, the cutting of fibres of the material to be extruded can be increased, but the apparatus of the reference cited is inefficient for the treatment of waste material.
The object of the present invention is to attain a method and an apparatus with which waste material can be treated efficiently.
The method of the invention is characterized in that the edges of the recesses and the openings of the rotor are sharp, in which case the waste material is conducted through the openings in such a manner that the waste material is ground by means of the sharp edges.
Further, the apparatus of the invention is characterized in that the edges of the recesses and the openings of the rotor are sharp in such a manner that the material passing through the openings is ground by means of the sharp edges.
The essential idea of the invention is that the apparatus has at least one conical rotor placed between two stators and at least the stator has recesses by means of which the material in the apparatus can be discharged when the rotor rotates. A further essential idea is that in the axial direction of the apparatus, the rotor has several openings through which the material to be treated is arranged to pass and that the edges of the openings and of the recesses of the stator are sharp to the effect that the material to be supplied is ground when it passes through the openings of the rotor. The idea of one preferred embodiment is that the recesses of the stator are at least partly discontinuous to the effect that when a recess ends, the material to be treated is forced through the opening of the rotor. The idea of a second preferred embodiment is that the rear end of the apparatus has recesses that transfer material outwards, which recesses lead to the outlet nozzle of the apparatus and which recesses are arranged into a sharp angle and the flights between the recesses are arranged to be so low that some of the material passes over the flights. The idea of a third preferred embodiment is that cooling means are arranged to the apparatus for cooling the material to be treated in the apparatus.
An advantage of the invention is that waste material, such as rubber, PEX, leather or textile waste, can be ground and treated efficiently. By arranging some of the material to pass over the flight between the recesses, the waste material at the flight can be grated into a smaller form. It can be ensured by cooling that the waste material will retain its powdery form.